textproduct: Quad Cities

KEY MESSAGES

- There remains an enhanced risk (level 3 of 5) for severe storms after 4 pm Tuesday south of a line from Sterling IL, to the Quad Cities, to Fairfield IA. Large hail greater than 2" and tornadoes will be the initial threats, transitioning to a wind threat late evening/overnight.

- Flash flood risk has decreased, but some localized flooding remains possible with any repeated rounds of storms overnight southeast of the Quad Cities.

- Colder and seasonable late week and into the weekend, with additional precipitation chances, some of which could be snow.

SHORT TERM /THROUGH TONIGHT/

Issued at 227 PM CDT Mon Mar 9 2026

A beautiful Spring-like day is unfolding outside, with wall to wall sunshine and temperatures at 1pm in the mid to upper 60s with a few locations hitting 70 degrees! Mixing depth on our 18z DVN sounding was already at 925mb, with a temp of 13C at that layer. Expect to see temps climb several more degrees today into the low to mid 70s enough to tie/break record highs for the day at least 3 of the 4 climate sites.

Tonight...a weak cold front will drop south over IA and stall between Hwy 30 and I-80. At the same time, a lake enhanced boundary off Lake Michigan will make inroads southwest over northern IL making for a challenging temperature/cloud forecast. North of these boundaries temperatures will drop into the 40s, with readings in the low to mid 50s south.

LONG TERM /TUESDAY THROUGH SUNDAY/

Issued at 227 PM CDT Mon Mar 9 2026

Active severe weather threat will be seen Tuesday primarily for the southeast half of the CWA. The exact placement and orientation of the warm front and any influence of the aforementioned lake enhanced boundary surging southwest will by key to the severe weather risk. CAM guidance has come in slightly further south compared to most global models resulting in a colder forecast across the north. The general consensus among all guidance has the front somewhere in the vicinity of a Fairfield IA to Galesburg IL line at 21z. I have attempted to incorporate this into the hourly temp/dewpoint forecast and we could very well have a 20-20 degree high temperature gradient tomorrow with mid 50s for highs near Freeport to close to 80 degrees by Keokuk! Have included record highs tomorrow, but it appears BRL will be the only one in jeopardy.

Severe Potential

A favorable environment will be in place Tuesday afternoon/early evening with MLCAPEs on the order of 1500 J/Kg, dewpoints in the low 60s, steepening mid level and low level lapse rates, and PWs in 1.1" range in the warm sector. Forecast soundings also show veering profiles with more than enough shear for updraft organization. The question becomes when the cap breaks before stronger forcing arrives late evening. Most CAMs and their respective ensembles keep the cap in place until at least 4pm, with CI occurring just to our southeast over central IL. Large hail >2" will be the initial concern as storms quickly become organized. In addition, some very impressive 0-1 and 0-3 SRH values over 200 and 400 m2/s2 along the frontal boundary will be in place to support the potential for tornadoes for any supercell that can latch onto the warm front. Residence time however may be short lived with Bunkers right motions remaining at 240-250 degrees at 35 kts as mentioned as a concern by the midnight shift. Any convection that develops north of the warm front will likely only pose a hail risk greater than 1" in the strongest cells. Bottom line, the potential remains for significant severe weather after 4 pm Tuesday until 10 pm primarily southeast of the Quad Cities.

This severe threat to quickly diminish late evening, but the arrival of the deeper synoptic scale lift and residual boundary will support additional rounds of showers and storms. The 12z HREF LPMM through 12z Wednesday shows pockets of 1-2 inches in areas that have seen 1-2 inches last week. WPC continues to highlight south of I-80 with a Slight Risk for excessive rainfall. Due to the ongoing drought much of the area will see beneficial rainfall, but any areas again that get into repeated activity given the anomalous moisture could wind up with several inches in a short time that could result in a localized flooding threat.

High pressure will build in behind this system for later Wednesday and Wednesday night ushering in drier and cooler conditions. The break from the active weather will be short- lived however, as deterministic models and ensembles support a clipper system diving through Upper Midwest and Great Lakes Thursday. Consensus takes the track of the low to our north, but strengthening warm advection/isentropic ascent will bring a good chance for a quick shot of mainly rain Thursday night - highest probabilities (60-70%) north of Hwy 30. Can't rule out a few flakes north of Hwy 20, but the strength of the WAA should keep this mostly if not all rain.

Heading into the weekend we remain in active W/NW flow aloft and will see periodic precipitation chances, as waves/clipper systems are shuttled down in/near the region. We will likely continue to see a roller coaster of temperatures - quick warming in the warm advection followed by cooling in the wake of these systems. Despite still some fairly large IQRs in NBM during this time they are centered near seasonal normals.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1202 PM CDT Mon Mar 9 2026

VFR conditions expected through most of the TAF cycle. A cold front will drop south across northern IA this evening before stalling out just south of I-80. Meanwhile, another backdoor cold front off Lake Michigan will move southwest towards northwest IL after 09z. Confidence is high enough to add MVFR fog to MLI and some MVFR stratus/fog at BRL ahead of this boundary with this issuance. Improvement is expected a few hours later around 15z tomorrow, with the warm front situated near/close to BRL. Just beyond this TAF period, expect isolated storms in the warm sector generally in the 21-01z timeframe primarily southeast of MLI and east of BRL.

CLIMATE

Issued at 333 AM CDT Mon Mar 9 2026

Record High Temperatures:

March 10: KBRL: 76 in 1955 KMLI: 74 in 1955

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.